Hydraulic machine



P 21, 1954 E. K. BENE'DEK I 2,689,531

H"DRAULIC MACHINE Original Filed Sept. 2 1945 4 Sheets-Sheet l INVENTOR.

97 22 ELEK K BENE DEK Sept. 21, 1954 E. K. BENEDEK 2,689,531

HYDRAULIC MACHINE Original Filed Sept. 27, 1945 50l FIG 4 4 Sheets-Sheet 2 504 Fl 6 6 SOI FIG 3 INVENTOR.

ELEK K BENEDEK Sept. 21, 1954 E. K. BENEDEK 2,689,

HYDRAULIC MACHINE Original Filed Sept. 27, 1945 4 Sheets-Sheet 3 Ill/ I I INVEN TOR.

ELEK K- BENEDEK- BY P 21, 1954 E. K. BENEDEK 2,689,531

HYDRAULIC MACHINE Original Filed Sept. 2'7, 1945 4 Sheets-Sheet 4 Patented Sept. 21, 1954 HYDRAULIC MACHINE Elek K. Benedek, Chicago, Ill. Melba L. Benedek, administratrix of Elek K. Benedek, deceased, assignor to Melba L. Benedek Original application September 27, 1945, Serial No. 618,890, now Patent No. 2,452,541, dated November 2, 1948. Divided and this application October 29, 1948, Serial No. 57,167

4 Claims. 1

This application is a division of my copending application Serial No. 618,890, filed September 7, 1945, now Patent No. 2,452,541, issued Novemher 2, 1948.

This invention relates to rotary hydraulic machines and more particularly to hydraulic pumps or motors of the kind which include a rotary barrel and a centrally located valve pintle about which the barrel rotates. The barrel is formed with a plurality of circumferentially deployed radial cylinders in which reciprocable pistons are mounted. Hydraulic machines of this general class are well known in the art and have been used extensively under exacting conditions of fluid pressure and rotative speed. Although numerous improvements and refinements have been contributed to the art in recent years, some difliculties remain to be eliminated or reduced in efiect. One of the difliculties is that of maintaining proper lubrication of the pintle and barrel, and of parts which transmit radial thrust to the recip-.

rocable pistons. Another undesirable characteristic of machines of this class heretofore provided has been their tendency to suck air into the cylinders resulting in noisy operation, and vibration frequently leading to break downs. In nearly all rotary hydraulic machines of the class referred to the driving torque is transmitted from the cylinderbarrel through the radial pistons themselves. At any stage of operation one half of the pintle surface and one half of the pistons are operating on suction strokes, and in prior art constructions the suction pistons must be operated without the protection of pressure film lubricant.

An object of the invention is to overcome these diflicultiesby providing an hydraulic machine of the class refered to in which a fluid tight chamber filled with working or lubricating fluid lubricates the coacting pintle and cylinder barrel surfaces which seal the working fluid of the cylinders by viscosity. With such a construction the corotating parts are sealed in a fllm of lubricant which assures complete and efiicient lubrication at all times. Furthermore the fluid in the chamber surrounds or covers the coacting surfaces of the pintle and cylinder barrel and prevents the sucking in of air between the surfaces, and provides lubricant under pressure between the pintle and its respectively associated barrel when the pump is performing a suction cycle. Thus the working fluid which also acts as a lubricant is maintained air-free and always available for pressure lubrication.

In accordance with the invention the foregoing stated object is achieved by providing a lubricant and working fluid containing space between two relatively rotating rotors, which clearance space is sealed at both ends of the barrel so that fluid will be maintained in said clearance space at all times of pump operations, durin suction as well as pressure periods.

Another object of the invention is to provide a construction of the character stated in which the fluid tight clearance is formed or provided by the cylinder barrel element, the pintle element, and sealing means so arranged between the barrel element and the pintle element as substantially to retain fluid between the two elements but so as to permit relative movement between the elements.

Another object of the invention is to provide a construction of the kind described above and in which means are provided for delivering fluid to the sealed clearance space.

Another object of the invention is to provide a construction of the kind referred to in which the body of fluid sealed in the clearance space minimizes the dry running and resultant excessive wearing of the suction side of the pintle and the coasting wall of the cylinder barrel bore, which havebeen characteristic of rotary hydraulic machines heretofore known.

Another object of the inventionis to provide an hydraulic machine having a fluid tight chamber in the dead-end bore of the barrel, the retained fluid of which chamber will supply supercharging fluid between the clearance space of the barrel and pintle, which fluid tends to repel incoming air at the left hand end of the pintle and barrel.

A further object of the invention is to provide an hydraulic machine including a pintleelement and a surrounding cylinder barrel element and novel and improved means for sealing the clearance between the pintle and the cylinder barrel bore on opposite sides of registering pintle and cylinder barrel parts. 1

A further object of this invention is to provide improved sealing means between pintle and barrel bore at both sides of registering pintle and cylinder barrel ports, which means include capillary clearance space whereby a small uniform capillary clearance is provided between closely finished barrel bore and lapped and ground pintle. In the capillary space the sealing occurs by the viscosity of working fluid which in this instance comprises high grade mineral oil, such as Gargoyle D. T. E. light, medium, heavy or extra-heavy.

aeeacei Since each grade of oil is suitable for a certain size capacity pump, it will be used with a certain clearance. Lighter oils are suitable for smaller pintles and smaller pumps, and heavier oils are suitable for larger pintles and'larger pumps. The capillary clearance has a linear magnitude of onehalf of one thousandth of an inch per one inch pintle diameter. Thus a one inch pintle requires one-half of a thousandth of an inch total diametral clearance, which amounts to one quarter'of one thousandth on the side. Under the term running clearance this specification means the amount of the side clearance around the entire periphery of pintle and barrel bore respectively. Diametral clearance meaning the total running clearance at diametrally opposite points of the pintle and barrel bore, which is twice as great as the radial or side clearance. But I do not limit my invention to any specific amount, as long as the clearance space issmall enough to seal the pressure and permit free rotation for the barrel.

Onemain object of this application is to combine the sealin effect of a capillary seal with the sealing effect of positive resilient "sealing means in such a manner that the capillary seal, at high operating pressures such as 3000 p. s. i., will take care of the pressure seal by permittinglimited predetermined pressure slip between the capillary parallel circular surfaces of the pintle and the barrel. While the resilient sealing means are not able to seal the high pressure, they are capable of sealing the air against the suction vacuum pressure, and thus preventing the suction-of air. The novel function achieved by inserting the resilient sealing rings between the pintle and barrel under compression, and in such a manner that the sealing means will take up any and all clearance between pintle and barrel, is that it will slide in pressure engagement against one'of the coactin'g pintle and barrel members. This pressure contact will not prevent axial flow of slip from the pintle and barrel parts axially out of the capillary clearance, but it is strong enough to prevent the reverse flow of air into the pump.

The prior art consistently neglected this important issue of the'efficient operation of a high pressure pump, and did not provide air seals against'thesuction-of air during suction periods of the pump. According to the spirit of this invention, a combination seal between pintle and barrel is so provided that one seal provides sufficient-resistance 'forsealing the' high pressurefluid during pressure cycles; to limit pressure losses to about five to ten percent-of the rated G. P. M. of the pump, while the other seal provides suction seal against the incoming air between the free ends of pintle and barrel respectively. It has been discovered that the exclusion of air from the pump and connected hydraulic system is not highly desirable but it is imperative. Elastic air under 3000 p. s. i., included and mixed with opcrating fiuid is very destructive, causes extreme vibrations in the system, leaks through the pipe joints where the oil itself is self sealingfbut the air opening'a way for'escape blows'the oil out with itself. Furthermore, a broken or cracked 4 Figure 1 is a central, horizontal, longitudinal sec-- tion taken on the center line ll of the pintle and the control rods of the stationary reactance, in Fig. 8.

Figure 2 is an enlarged fragmentary section of the suction seal as it is assembled-between pintle sealing means in accordance with one feature of the invention.

Figure 4 is a view similar to Figure 3 but showing the sealing means in connection with bushing bearings-instead of the anti-friction bearings shown in Figure 3.

Figure 5 is an enlarged fragmentary fractional view of my novel sealing means, taken from Figure 4.

Figures 6 and. '7 are side and sectional views of a resilient sealing ring provided as one embodiment of my novel resilient sealing means.

Figure 8 is an endvie'w in cross-section further illustrating the hydraulic machine shown in Figure 1.

Figure 9 is an enlarged sectional view taken through the pintle, barrel and resilient seal assembly in Fig. 1, showing the pintle, barrel and the resilient seal in concentric operating positions.

Fig. lo'show's an enlarged'sectional view take through the pintle, barrel and resilient'seal-assembly inFig. 1, showing the three elements in eccentric operating positions.

Figure 1-1 is an enlarged sectional view taken through the pint1e,=-barrel and resilient seal. assembly in Fig. -1,showing the three elements in eccentric relative positionsto one another.

Fig. lZ'isa diagram showingthe circle of eccen tricity onwhich the center of the cylinder barrel and the pintlerespectively are moving during the operation ofthe two. This diagram corresponds to the showing of Fig. 10.

Fig. 13 isa diagramshowing the circle of eccentricity-on which the center of the cylinder barrel and the pintle are -moving during the operation of the two. This diagram illustrates the showing Fig. 11. p V

The machine shown in Figures land 2 include a casing etprovided withan end plate held inplace by screws'96. A pintle ill isformed with a valve portion Q8 and with-a mounting portion 99 fixedly 'secured-in 'a casingboss Hit. A cylinder barrel I0! is mounted for rotation-about the pintle portion 8 and is connected to a shaft cap H32 by means of screws 153*. The shartor cap is journaledin-ball bearings-I05 carried by the casing end plate 435.

The cylinder barrel i0! is formed with a'single set of circumferentially deployed radial cylinders [05 equipped with reciprocable'pistons Hi6. Pins I51 respectively fitted'to the outer ends of the pistons engage 'reactance tracks 58 and liiiicarried by a rotatable inner reactance assembly formed of two halves secured together with bolts HI. The inner reactance element is mounted "for-rotation by ball bearings H2 carried" by an outer reactance structure comprising end plates I I3 s'ecured'to a'central ring H4 by means-of screws H5.

Referring now more particularly to Figures 1 to 7, to the novel, features of the form shown in this-division, namely to the pintle 99, cylinder barrel llll and interposed resilient sealing rings 122-122, and the capillary sealing means'C, as

in Figure 2, it will be seen that the invention comprises two main features, and their combination. Namely, first the effect of a uniformly distributed and capillary clearance space C, which means seals by the viscosity of the oil (the Working fluid) and the new phenomena of varying the sealing effect of the capillary seal by varying the concentricity of the pintle 91 and the barrel l 1. The second feature of this invention lies in the application of resilient sealing means, such as l22l22 made out of compressible seal material, such as various, compounds of artificial rubber, cork, neoprene, etc. Also important non-metallic seal is the graphite and its various mixtures with bearing metals such as lead, copper, tin, etc., whereby the non-metallic seal ring may slide upon the pintle in direct contact with the pintle as shown more specifically in the enlarged view of Figure 2.

The third and really the resultant phenomena caused by the combination of the above two sealing means'is the effect of direct sealing of the capillary clearance C by the non-metallic or resilient seals |22l22. The seals 122-422 will prevent the suction port H6 from taking in air through the capillary clearance C, which obviously occurs when a sustained long range suction period is taking place in the pump. During a long suction period, whenthere is no new slip coming forth, and the oil film contained in the circular concentric clearance C between pintle and barrel gradually will be sucked into the suction port H6 and thus destroyed, air will enter into the suction port I I 6, contaminate the working fluid and cause destructive vibration and noise in the pump and in the interconnected hydraulicsystem. Additionally, the intruding suction air dries up and destroys all vestige of the oil film between pintle and barrel, at least upon the suction side area of the working portions 91 and 98 of the pintle.

When the oil film is sucked out under the barrel, in the construction of Figure 1, the barrel will drop down and will touch the upper side of the pintle in a metal to metal rubbing contact. Equally detrimental is the phenomena which occurs after the pintle and barrel come intometal to metal contact on the one side of the pintle.

This is the phenomena of the oifset eccentric position of the pintle and barrel and the distortion of the previously uniform circumferential capillary clearance C between pintle and barrel. The metallic contact between pintle and barrel causes the rapid wear and eventual galling, seizure and welding of the two corotating elements, while the eccentric position of the previously uniform clearance C will increase the working slip to two to three times of its previous normal value, as hereinabove was also mentioned. c

In the particular construction of Figure 1 the cylinder barrel IN, the pintle mid portion around the pintle port area B, and the sealing rings l22-I22 at both sides of the port HSform a fluid tight chamber to retain lubricating pressure fiuid for this area. The source of fluid is the pressure in port I [6, which tries to escape right and left under the operating pressure. It is obvious as previously described that to prevent excessive leakage between pintle and barrel, the capillary clearance C and seal length between the port I I6 and the seal rings l22l22 are provided to effect the so-called high pressure seal. The so-called suction seal," to prevent the suction of air and to keep the above named clearance.

space C with fluid at whatever pressure for the sake of capillary lubrication, is the main duty of the resilient seal 122-422. As long as the pump is in operation the pump pressure port I IE will deliver discharge fluid into the closed chamber C. It is true that the suction port H6, opposite to the pressure port H6 is trying to suck in right away whatever film fluid it can from this closed clearance chamber C, so that the pressure discharge in port HG-tends to be short circuited and flow into suction port I IS. However, only the excess or high pressure slip can escape the resilient seals l22-l22, and not the low pressure or idling pressure, which will be retained for air seal arid lubrication.

In operation, when the cylinder barrel is rotated and the reactance structures are set eccentrically to the pintle axis, the pistons will be reciprocated so as to draw in and expel fluid through pintle ports H6 and H6. Preferably the slip of fluid along the pintle is minimized by the provision of sealing rings I22 which assist in preventing the sucking in of air at the inner ends of the cylinders. The rings I22 form the ends of a pressure film chamber between the pintle and cylinder barrel bore and thereby confine a pressurized film of lubricant circumferentiallyaround the entire intervening portion of the pintle instead of allowing the lubricant to leak along the pintle to the ends of the cylinder barrel. Since fluid under pressure leaks along the pintle to act on the end of the shaft cap I02, axial pressure thrust on the cap and on the barrel will be taken up by bearing I04.

The provision of sealing rings between the pintle and the wall of the barrel bore is advantageous generally in hydraulic machines including a cylinder barrel element and a pintle element, one of which elements is rotatable relatively to the other. Figure 3 shows a simple sub-assembly including a pintle 500, a cylinder barrel 50!, and anti-friction bearings 502 mounting the elements 500 and 50! for rotation, one with respect to the other. In order to seal the small workingclearance C between the pintle and barrel bore wall, non-metallic sealing rings 503 are mounted in seats 504 in the barrel 50l so as to have intimate running contact with the pintle onopposite sides of the usual registering pintle and barrel ports 505-406. The non-metallic, e. g. carbon or graphite rings 503 can be fitted so closely to the pintle as to prevent the loss of lubricant from the clearance between the pintle and barrel, and also to prevent the sucking ofair through this clearance and into the cylinder or cylinders. The

barrel-pintle sealing rings 503 are particularly advantageous when used in connection with modern axially short pintle and barrel combinations.

The construction illustrated in Figure 4 is similar to that shown in Figure 3 differing only in the use of plain bushing bearings 502 in place of the anti-friction bearings 502 shown in Figure 3. The non-metallic sealing rings 503 may be used advantageously in connection with either of these or with other types of bearings.

In effect, the prevention of loss of the pressure slip by the opposite sealing means l212l22 not only provides an efficient and economic means for lubrication of the pintle, but it prevents destructive wear, suction of air and subsequent noise and vibration not only in the pump, but in the entire system. The fact is that the slipwhen retained in this manner constitutes a pressure oil cushion between pintle and barrel, which pressure is sufficient to keep the pintleandbarrel;

503-503 as in Figure 3, and Figure 4 are inserted between pintle and barrel, pressurized fluid body is trapped and preserved in the telescoping capillary clearance C therebetween in such a manner that during a subsequent pressure cycle, when the pressure acts in one port of the pintle and creates a heavy hydrostatic wedging action between the coacting surfaces, the trapped fluid will resist the wedging action and permit the new pressure to propagate in the entire body of entrapped lubricant and thus balance the entirepressurized body of oil and with it the pintle with respect to the barrel. On the other hand, if before an immediate pressure impulse or shock, the suction side of the pintle is empty, the wedging action of the pressure will pull the pintle and the barrel into metallic contact, and no balancing can take place, because there is no fluid on the suction side of the pintle and barrel which would serve as fluid medium to either take'up and resist thewedging action by pressure, or by transmitting pressure through propagation of pressure impulse, from the pressure side to the suction side or" the relatively rotating assembly of the pintle 500 and barrel 501.

Thus in the concept of the invention, there is an automatic pressure balancing method which comprises the provision of a fluid tight chamber such as is provided by end seals 50:3503, pintle 500 and barrel 50!, a uniform clearance space C between 500 and EDI, and fluid pressure means to maintain the fluid tight chamber with working fluid atallphases of the pump operation.

Figure 5 also shows thatwhere a sleeve bearing is used in combination with pressure seals 503, the preferred clearance between the pintle and the sleeve is the same as the preferred clearance between pintle 5M and barrel 50!.

The'seal rings 563 are cast or molded and finlshed to such sizes as to give the necessary sealing action around its entire periphery by compression or close machined fit, like in the case of graphite rings. The sealing pressure of these rings shall be around a couple hundred pounds per square inch, so that actual pressure will be maintained in the sealed chamber C. The compression on the packing 503 is greater than the pressure to be sealed in chamber C.

The operation of my novel resilient seal rings, shown in Fig. 1 may best be described and understood in connection with Fig. 9, Fig. 10 and Fig. 11 respectively. This invention supplements the heretofore conventional close-ground metallic seal between pintle i! and barrel I01 by resilient, non-metallic or metalloid seal rings |22-l22 at opposite sides of the pintle ports G l l6 respectively. By this: combination of the viscous fluid seal, which is the metallic or inorganic seal with the non-metallic or metalloid seal, many heretofore unknown advantages are obtained. One basic advantage is the one shown in the Figures v9, and 11, whereby the relative eccentric rotation of pintle '9'1' and barrel I01 upon the eccentricity circles R=C in Fig. 12

and in Fig. 13 respectively, the metallic clearance C provided for the relative rotation of pintle and.

barrel does not remain concentric to the pintle and barrel as shown in Fig. 9, but due to the diametrally opposite location of the suction and pressure ports and H 6 of the pintle 91, the pintle and. barrel always tend to rotate in an eccentric manner, as shown in Fig. 10 and Fig. 11. respectively.

Fig. 12 and Fig. 13 show this eccentric relative rotation on the enlarged eccentricity circles having for radii R the amount of C, the evently distributed pintle and barrel clearance. Thus, in Fig. 9 the ideal relative position, for which this invention is aiming, by the provision of seals l22l22 is shown. In this figure, the resilient seal 122 and the seal clearance C are also concentric with the pintle 9 1 and barrel I101 and? all are disposed about one center of rotation marked O in Fig. 9. InFig. 10, however, two rotational centers manifest, such as O). and 02-, '01 being. located on the top, 02. on the bottom of the circle of eccentricity as" in Fig. 12. In Fig. 11, on. the other hand, 02 appears on the top, 01 on the bottom of the circle of relative eccentricity, as a consequence of a pressure and flow reversal of the variable delivery reversible pumps. the l'ocationof the center of relative rotation are reflected by Fig. 12' and Fig. 13, the facts pertaining to the variation of the bodily shape of the resilient seal I22 are shown in Fig. 9, Fig. 10 and Fig. 11. The. change in the shape of the resilient seal is just capable to seal the eccentric clearance spaces C1, C2, C3 respectively, in such a manner that. the high pressure viscous seal will be additionally' increased by the sealing power of resilient member I22 and at thesame time the entrance of air duringsuction cycles will be entirely eliminatedthe, viscosity of air is much less than the viscosity 'of oils, it is obvious that the large openings between pintle and barrel as shown by the. dotted lines of C1, C2 and C3 in Fig. 9, Fig. 10 and Fig. 11 would provide prohibitive. entrance for low viscous. fluids. such asxair, into the pump during: suction. periods. While the important structural merits of the invention .are shown in Fig- .1, it is obvious that the non-metallic or metalloidseals l:221l.22 are so. located in thebarrel ml or in the pintle 9.1, as the case maybe, that the. high pressure at sudden development cannot blow out the seals l22-t22, because they are. well recessed, housed .and protected in one of thesaid members only, while they are disposed in axially floating position with respect to the other of the. said members.

The distancev of. the seals 122-122 with respect to; the pressure and suction ports HBI.I6 may vary as much as the pintle length, yet .due to the linear drop of pressurefrom the ports out tov the right or to the left, it will be seen that in any disposed axial positions the seals .l-22-ll22 will achieve substantially the same sealing, lubricatmg, balancing and centering effects. for the pintle 9'1 and the barrel 101'. When the rings l2:i'l22v are made outof synthetic or natural rubber, under the high pressure of the pressure port HE they will be tightly pressed in their respective grooves and will seal also the viscous passages C as shown in Fig. 2. Fig. 1 also shows similar effects of .rings ill-1| H for the benefit of the pistons Hi6 and cylinders I05 and associated thrust transmitting means Ill! and H18 respectively. These lattertadvantages are claimed andmorespecifically described inmy U. S. Patent No.'2, .-'52,541., issued :Nov. 2', 1948'.

While I Fig. 8 shows more particularly the pressure and exhaust ports H6 and H6, and that one-half of the total number of pistons are under pressure while the other half are under negative pressure, that is vacuum, It is this vacuum, which is more dangerous for the life of the piston and cylinder assemblies than the pressure, for which this invention provides positive remedies in the form of better lubrication, by the elimination of friction and air between the suction pistons and the suction cylinders and between the suction half of the pintle and barrel respectively.

The importance of the advantage obtained by providing the fluid containing sealed chamber can be appreciated fully only when the importance of lubrication is considered. For instance, in purely mechanical machines complete lubrication is provided, but in a conventional pump, one-half of the pintle surface is running without lubrication. With conventional or previously known structures the coefficients of friction of the pintle and barrel on the suction side may be about .3 to .5, whereas with pressure lubrication afforded by the present invention the coefiicient will be reduced to less than .01. The above named improvement is necessitated by the novel pump structure which reduced a large capacity pump to relatively small component parts. This could not have been achieved without the provision of more effective lubrication than heretofore was provided by the prior art.

Although several specific embodiments of this invention are herein shown and described, it will be understood that numerous details of the construction shown may be altered or omitted without departing from the spirit of this invention as defined by the following claims.

I claim:

1. In an hydraulic machine of the character described, a relatively fixed pintle, a cylinder barrel rotatably mounted on said pintle and having a central disc portion with radially extending lateral side walls limiting said disc portion, pistons reciprocable respectively in said cylinders and projecting beyond the outer ends thereof; a reactance structure having axially separable side walls lying in face-to-face abutting relation with the adjacent lateral side walls of the disc portion of said barrel and surrounding and eccentric to the axis of the pintle; thrust transmitting means interposed between said reactance structure and the outer ends of the pistons; means providing fluid seal between said lateral side faces of said cylinder barrel and between said axially separable side members of said reactance structure, said sealing means said cylinder and said reactance structure providing a substantially fluid tight chamber pressure fluid lubricating bath and accommodating said outer ends of the pistons, associated cylinders and said thrust transmitting means respectively, for providing fluid seal and forced feed lubrication for said pistons and cylinders and said thrust transmitting means respectively, said means including a seal and groove-way combination, said seal grooveway being provided in one of the said barrel disc walls and axially separable side members of said reactance structure and operable against the other of said members.

2. In an hydraulic machine of the character described, a relatively fixed pintle, a cylinder barrel rotatably mounted on said pintle and having a central disc portion with radially extending lateral side walls limiting said disc portion, pistons reciprocable respectively in said 10 cylinders and projecting beyond the outer ends thereof; a reactance structure having axially separable side walls lying in face-to-face abutting relation with the adjacent lateral side walls i of the disc portion of said barrel and surrounding and eccentric to the axis of the pintle; thrust transmitting means interposed between said reactance structure and the outer ends of the pistons; hydraulic means providing fluid seal between said lateral side faces of said cylinder barrel and between said axially separable side members of said reactance structure, said sealing means said cylinder and said reactance structure forming a substantially fluid tight chamber for accommodating said outer ends of the pistons and associated cylinders, said hydraulic means including metalloid sealing rings, said rings being carried by one and engaged by the other of said barrel and. reactance structure respectively.

3. In an hydraulic machine of the character described, a relatively fixed pintle, a cylinder barrel rotatably mounted on said pintle and having a central disc portion with radially extending lateral side walls limiting said disc portion, pistons reciprocable respectively in said cylinders and projecting beyond the outer ends thereof; a reactance structure having axially separable side walls lying in face-to-face abutting relation with the adjacent lateral side walls of the disc portion of said barrel and surrounding and eccentric to the axis of the pintle; thrust transmitting means interposed between said reactance structure and the outer ends of the pistons; means providing fluid seal between said lateral side faces of saidcylinder barrel and between said axially separable side members of said reactance structure, said sealing means said cylinder and said reactance structure providing a substantially fluid tight chamber for accomir-io dating said outer ends of the pistons and associated cylinders, said means including resilient sealing rings; said sealing rings being arranged in paired assemblies between each side of said cylinder barrel, and the coactingffa'ces of said reactance structure respectively. V

4. In an hydraulic machine of the character described, a relatively fixed pintle, a cylinder barrel rotatably mounted on said pintle and having a central disc portion with radially extending lateral side walls limiting said disc portion, pistons reciprocable respectivelyin said cylinders and projecting beyond the outer ends thereof; a reactance structure having axially separable side walls lying in face-to-face abutting relation with the adjacent lateral side walls of the disc portion of said barrel and surrounding and eccentric to the axis of the pintle; thrust transmitting means interposed between said reactance structure and the outer ends of the pistons; means providing fluid seal between said lateral side faces of said cylinder barrel and between said axially separable side members of said reactance structure, said sealing means said cylinder and said reactance structure providing a substantially fluid tight chamber for accommodating said outer ends of the pistons and associated cylinders, said means including resilient sealing rings; said sealing rings being arranged in paired assemblies between each side of said cylinder barrel and the coacting faces of the associated reactance structure, and being under compressive forces in all directions of the space to seal a portion of the slip fluid in said fluid tight chamber, and provide an oil bath for said 11: pistons and cylinders and coacting thrust trans- Ngmbgg; mitting means respectively. 2,159,245"

H I v n l 2,209,224- References Citd in th'efile of this patent 2213236 UNITED 'STATES PATENTS': 2 2,273,468: l 2,452,541 Number 7 Name" Date 13655;,339 Rix Jan. 3, 1928 1,"763,565 Parker June10, 1930 Number 2'; 021,353 Ernst Nov. 19'; 1935 244,631- 2';1'30,'2 98 Ernst" Spt. 13, 1938 Name Date Benedek May 23,1939.- Ernst .July 23,1940: Benedekfli Sept. 3; 1940 Ferris 1 Feb. 17, 1942 Benedek. N0v.-2, 194i FOREIGN PATENTS Country Date" Great Britain 011925. 

